The present invention relates to a method for extending the life of cut flowers such as roses. In particular, the present invention relates to the use of an aqueous solution of chlorine dioxide for extending the life of such cut flowers.
It is known that the useful lifetime of cut flowers can be extended by refrigeration and by use of certain chemical preservatives. The fact that many flower varieties are shipped as cut flowers over long distances has provided a need for improved methods of extending the life of cut flowers. Placing cut flowers in water affords some measure of preservation by keeping the flowers hydrated, but chemical preservatives are often added to water solutions to further extend the life of the cut flower.
Among the chemical preservatives currently in use are carbohydrates such as sucrose, fructose and glucose, acidifing agents for producing a solution pH of 3 to 7, agents for preventing stem blockage, etc. Several preservative compositions which contain various mixtures of the foregoing are commercially available, e.g., Chrysal(trademark), Floralife(trademark), and the like.
Frequently, bleach is used as a biocide by florists to sterilize storage containers which are to hold the cut flowers as well as for sterilization of pumping apparatus and tubing used to deliver storage solution to the storage containers. Although bleach is quite cheap, it produces an undesirable basic pH in the solution and florists do not like handling bleach solutions. Moreover, the bleach remains in the storage solution for a prolonged period of time and is toxic to many flowers which are stored in such bleach solutions for prolonged periods of time.
It is the object of the present invention to provide a method for extending the life of cut flowers, especially roses.
The method of the present invention comprises: (a) providing a storage solution containing chlorine dioxide; and (b) bathing the stem of the cut flower in the solution.
As mentioned above, the method of the present invention comprises: (a) providing a storage solution containing chlorine dioxide; and (b) bathing the stem of the cut flower in the solution. In general, the concentration of the chlorine dioxide in the solution is in the range of about 1 to about 25 parts per million, based on the weight of the solution. Preferably, the concentration of the chlorine dioxide in the solution is in the range of 4 to 10 parts per million, based on the weight of the solution. In order to insure the maximum beneficial effect of the solution, it is preferred that the stems of the cut flowers be immersed in the solution immediately after harvesting the flowers.
Especially good results have been achieved wherein the cut flower is a rose. Preferably, the rose is again cut again, while submerged either in water which is subsequently converted into the solution or in the solution itself, in order to avoid the formation of air bubbles in the stem which would impede the transport of the solution through the stem.
The storage solution is prepared by adding a combination of an alkali metal or alkaline earth metal chlorite, e.g., sodium chlorite, and a solid acid, e.g., sodium bisulfate, to water. Preferably, the molar ratio of chlorite to acid in the combination is in the range of about 0.5:1 to about 1.5:1. In general, the combination is present in the form of a massive body, e.g., in the form of agglomerates or tablets. Tablets represent a convenient form for preparation of the solution. In general, a tablet having a weight of about 0.1 to about 10 grams, preferably a weight of 1 to 5 grams has been found to be most useful for preparing the solution. The solution is readily prepared by adding 1-3 tablets to about one gallon of water.
Preferably, the tablet contains one or more desiccants present in an amount of about 5 to about 20 wt. %, based on the weight of the tablet. Suitable desiccants include calcium chloride, magnesium chloride and magnesium sulfate. It is also preferred that the tablet includes one or more promoters, present in an amount of about 1 to about 10 wt. %, based on the weight of the tablet. Suitable promoters include sodium chloride, potassium chloride and an isocyanurate.
It is also preferred that the tablet contains one or more sugars, present in an amount of about 0.5 to about 10 grams per gallon of solution. Suitable sugars include ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose, talose, fructose, alkyl-xcex1-glycosides, aryl-xcex1-glycosides, alkyl-xcex2-glycosides, aryl-xcex2-glycosides, lactose, maltose, cellobiose, gentiobiose, turanose, iso-maltose, laminaribose, melibiose, sucrose, trehalose, raffinose and gentianose.
In order to accelerate the dissolution the tablet in the water to form the solution, it is preferred that the tablet contain an effervescing agent, e.g., sodium bicarbonate, in an amount of about 2 to about 12 wt. % based on the weight of the tablet.